Controllable cooling system for internal-combustion engines



I p 1952 F. K. H. NALLINGER 2,611,347

CONTROLLABLE COOLING SYSTEM FOR INTERNAL-COMBUSTION ENGINES Filed Jan. 13, 1950 .ZTVl/ENT l6 I ZGIEJK'IcH' MvuJMzg Patented Sept. 23, 1952 co raoLLABLE COOLING srs'rssiroa n1- 'r nNAL-coMBUsrIoN' nomes. V

Friedrich K. H. Naliinger, Stuttgart, Germany, assignor to Daimler-Benz Aktiengesellschaft, .S'tuttgart-Unterturkheim, Germany Application January 13, 1950,, Serial N 0. 138,279

In Germany December 6, 1948 is Claims. (01. 123-4112) This invention'relates to a controllable cooling system, in particular for internal'combustion engines for vehicles.

To obtain a more efficient cooling, the cooling systems-of internal combustion engines for motor vehicles a rule are provided with afan '(e. g.

also with an air pressure increasing blower). The power consumed ior'this'purpose is, however,

only in part usefull utilized, sincefor the most tionthereto in longitudinal direction. .Positive driving connection between the pulleyand the shaft Z can be established by means of the clutch m,.one half on of which being slidably, butunrotatably mounted on the shaft Z and connected by means of a double-armed lever n orthe like to a springloadedpistono in such a manner that the latter is-maintained by the spring p in the oil position, the on-position being .efiected under part of its operating timewith the conventional the action of alpressure liquid in the cylinder. q ran drive arrangementsfor instance up to 80% by establishing frictional engagement between of the operating time andmore-the coolingefthe clutch halves mi and m2, of which m2 is posifect of the head-wind alone willsufiice in general tive ly connected to the pulley is. i without there being the necessity tohave the fan The pressure liquid, e. g. the lubricating oil of in operation. During this. time the fan neceslithe-engineerany other liquid suitable for the sarily continues running and causeswaste power purpose in view, is. withdrawn (as diagrammatiand-noise. .cally illustrated in the drawings) from a tank r The main object of the invention is to provide and supplied by the pump 5 through conduitsi for a more economicoperationof the cooling systo an operating. piston 75 having a groove t1 and a tem and accordingly one of its features consists bore 152 and beingsubject to adjustmentby a therin that the fan is put intooperation only or submostat u conveniently. located anterior to the stantially only if the cooling eiiect' of the cooling junction of the by-pass conduit g with the return system with the fan being disengaged does no flow conduit d of the cooling water. A conduit 1) longer sufiice to ensure a sufficiently low thermal connects the casing of the operating piston to the state of the engine. Throwing inor outof the 25. cylinder q. Areturnlinewconducts the oil from fan is effected in this case in particular in dethe spacer of the casingof the slide valve back pendence upon the temperature of the coolant or into the tank. 1'. Further thereis a byepassconof the intercoolingmeans leaving the cooler, e. g. duit 11 which in the lef -hand position of the opof the coolingwater circulating through the en- 'erating piston connects the ,bore tztothespace at, gine and a recooler, conveniently by means of and a pressure relief valve 2 between the conduits a thermostat between recooler and engine. .siandw.

To engage or disengage the fan a mechanically, The modeof operation of the form of embodihydraulically, pneumaticallyor electrically actu- .ment described is as follows:

ated clutch may be used. If desired, also a step- The thermostat u, is under normal conditions, wise or infinitely variable disconnectable gear 5 .below a predetermined elevated temperatureof ..may be'provided anteriortothe fan. the cooling .water flowing, through conduit'd, in

. Oneform of embodimentof theinvention 'in- ,itscontracted, state, ,wh ich meansthatptheoper- I eluding ahydraulically actuated mechanic-clutch ating piston isin its left-hand position. In this .is diagrammatically shown in; the accompanying casethepump s, which is e. gecontinually driven drawing. 7 40 .bythe engine. .(or which, whencontrolled by the The cooling water leaving theengine. a flows -;thermostat 14,-, may under normalconditi'ons also through conduit 12 to the radiator (recooler) 0 r ain inits foff--nosition) ;deliverstheliquid and from there through conduit 01 and a cooling through the control bore t2 to the Icy-pass coni water circulating pump e back to theengine a. .duityandfrom there throughthe spacexof the H A by-pass conduit 9 controlled byathermostat f. slide valve and; the return flow line w back to the branches off the conduit b and serves at lower tank 1. The space, stand consequently theintemperatures of the cooling water to feedthe terionof h c lind r. q in n ction therewith cooling water directly back to the return fiovvconin this. position of {the operatin piston through duitd without passing it through the cooler c. the conduit 'u'are"substantially,wi-thoutpositive A' fan i driven by a belt it sucks cooling airv pressure, the clutch m being thus disengaged through the radiatorc in the direction of. the .under the actionof the spring p dtb f t a arrows resp. aids to increase the coolingeffect of standstill. Recoolingof the'cooling-water in the the head-Wind impinging thecooler. Q radiatorcis exclusively efiected b gh h w The pulley is loosely mounted on its drive. shaft .wind, the cooling effect being controlledpy. the z, e. g. the valve timing shaft, but in fixed re1afl ti c v n to ediu tthe fan shaft or at any other suitable place.

thermostat so as to include the radiator in the cooling water circulation already at a lower temperature than usual, in order to provide for a sufficient exchange of heat in spite of the fan being put out of operation.

In the event of the cooling effect of the radiator c impinged only by the head-wind being no longer suflicient (e. g. even if the total quantity of cooling water flowing through the engine is passed through the radiator by means of the thermostat j) to maintain the cooling liquid at the low temperature level required, the expanding thermostat u interrupts the connection between 1; and x, and between 1/ and 132 or s1 resp. and, as illustrated in the drawing, establishes the connection between the conduits s1 and 1) through the bore 752. The pump s therefore forces the liquid into the cylinder q at a pressure determined by the load applied by the spring to the valve .2. The piston o is displaced to the right against the action of the spring I which results in coupling the fan with its drive shaft Z by means of the clutch m. The liquid delivered in excess by the pump 5 is returned through 2 and w.

If the temperature in d is lowered so that the piston t is urged again towards the left, the conduit '0 and the cylinder q resp. are connected again through a: to 10, whereby owing to the expansion of the spring p the liquid is forced out of the cylinder q and the fan disconnected.

Accordingly the fan will be put into operation only or substantially only if all other possibilities of recooling the cooling water are already exhausted. For reasons of safety the clutching of the fan may, of course, be effected also more or less earlier. Likewise the fan may be put out of operation, e. g. by friction on the piston t or the like, with a certain delay with relation to its throwing in (i. e. only at a lower temperature than the throwing in of the fan) to avoid a continuously repeated connection and disconnection of the fan within the range of the control temperature.

Instead of being mounted on the drive shaft 1, the clutch may be arranged also directly on the The clutch may be designed e. g. also as an electrically or hydraulically operated clutch, for instance as a fiuid coupling capable of being engaged and disengaged by filling and emptying. As a further modification e. g. a disconnectable fluid converter, a planetary gear, an infinitely variable friction gear or the like may be used, providing an infinitely variable transmission in dependence upon the temperature of the cooling water.

In the case of air-cooled engines, throwing in or out of the fan or of the blower may be effected in dependence upon the temperature of the heated cooling air. If desired, provision can be made also to efiect connection and disconnection in dependence of the thermal state of the engine.

While this invention has been described in connection with road vehicles, it is understood, that it may find application also to all other types of vehicles e. g. rail cars, aircrafts and watercrafts and correspondingly to all engines operating under similar conditions.

What I claim is:

1'. A recooling device for the cooling liquid of an internal combustion engine for vehicles, comprising a cooler for said cooling liquid, delivery means for a cooling medium to increase the heat exchange in said cooler from the cooling liquid to the cooling medium, control means responsive to the temperature of the cooling liquid for controlling the operation of the cooler, and control means responsive to the temperature of the cooling liquid for controlling the operation of the delivery means, both said control means being so constructed that an increasing temperature of the cooling liquid increases first the operation of said cooler and thereafter the operation of said delivery means.

2. A device as specified in claim 1, wherein both said control means are so constructed as to disconnect the delivery means below a predetermined temperature of the cooling liquid and to connect said delivery means above said temperature.

3. A device as specified in claim 1 wherein both said control means are so constructed that the cooler and delivery means are not connected until the cooling fluid exceeds an individual temperature for each of the cooler and delivery means and are disconnected when it falls below said individual temperatures.

4. A recooling device for the cooling liquid of an internal combustion engine, comprising a cooler for the cooling liquid, a supply conduit connecting the engine and the cooler, a return flow conduit leading from the cooler to the engine, a by-pass between the said conduits, thermostatic means controlling the by-pass, a fan for delivering air through said cooler, control means for controlling the delivery rate of the fan, and thermostatic means for controlling said control means.

5. A recooling device for the cooling liquid of an internal combustion engine, comprising a cooler for the cooling fluid, a supply conduit connecting the engine and the cooler, a return flow conduit leading from the cooler to the engine, a by-pass between the said conduits, thermostatic means controlling the by-pass, a fan for delivering air through said cooler, a. control device for controlling the output of the fan, and thermostatic means for controlling said control means.

6. A recooling device for the cooling liquid of an internal combustion engine, comprising a cooler for the cooling liquid, a supply conduit connecting engine and cooler, a return flow conduit leading from the cooler to the engine, a thermostatically controlled by-pass between the supply and return conduits, a fan for delivering air through said cooler, a thermostat in said return flow conduit and control means for controlling the fan including driving means for the fan, a clutch device for disconnecting the fan from its drive and control means for the clutch associated with said thermostat capable of disengaging the clutch below a predetermined temperature of the cooling liquid at the place of the thermostat and engaging said clutch above said temperature for the purpose of driving the fan.

7. A recooling device for the cooling liquid of an internal combustion engine, comprising a cooler for the cooling liquid, a supply conduit from the engine to the cooler, a return flow conduit from the cooler to the engine, a thermostatically controlled by-pass between the supply and return conduits, a fan for delivering air through said cooler, driving means for said fan, a clutch for disconnecting the fan from its driving means, a device responding to the thermal state of the engine and actuating means associated with said last mentioned device for said clutch capable of engaging said clutch only at an increased thermal state of the engine thereby putting the fan into operation.

8. A device as specified in claim 7, wherein said actuating means comprise control means for a servomotor operating in dependence upon the thermal state of the engine and a transmission device eflecting the operation of the clutch for said servomotor.

9. A recooling device for the cooling liquid of an internal combustion engine comprising a cooler for the cooling liquid, a fan for delivering air through said cooler, driving means for the fan, a clutch permitting the disconnection of the fan from its drive, a supply conduit connecting engine and cooler, a, return flow conduit from the cooler to the engine, a thermostatically controlled by-pass between said supply and return conduits, a thermostat in said return flow conduit, an operating piston controlled by said thermostat for a servomotor, a, transmission device for said servomotor actuating said clutch in such a manner that at a low temperature of the cooling liquid at the thermostat the clutch is in its disengaged position, while being in its engaged position at a high temperature of said cooling liquid.

10. A device as specified in claim 7 wherein the clutch is designed as a smoothly operating clutch.

11. A device as specified in claim 7 wherein the clutch is designed as a friction clutch.

12. A device as specified in claim 5 in combination with a thermostat for controlling the bypass conduit and located in the supply conduit.

13. A recooling device for the cooling fluid of an internal combustion engine, comprising a cooler for the cooling fluid, a supply conduit from the engine to the cooler, a return flow conduit from the cooler to the engine, a by-pass between the supply and return conduits, a thermostat located in the by-pass for controlling the flow of fluid through the by-pass in response to the temperature of the cooling fluid, a fan for delivering air through the cooler, a further thermostat in the return conduit, and a control device for controlling the output of the fan in response to the control position of the further thermostat, both thermostats being so calibrated that upon an increase in the temperature of the cooling fluid the by-pass is first closed and the fan is thereafter rendered operative.

14. A device according to claim 13 wherein the by-pass is so arranged that it opens into the return conduit upstream of the thermostat controlling the fan.

15. A recooling device for the cooling fluid of an internal combustion engine, comprising a cooler for the cooling fluid, a supply conduit from the engine to the cooler, a return flow conduit from the cooler to the engine, thermostatic control means in the supply conduit for controlling the cooling action exerted upon the cooling fluid, thermostatic control means in the return conduit for controlling the cooling action exerted upon the cooling fluid, the said means being so constructed and calibrated relatively to each other that the first said means will respond earlier than the second said means to an increasing temperature of the cooling fluid.

16. A device according to claim 15 wherein the first said means comprise means for controlling the cross-sectional area of flow of the cooling fluid through the cooler and the last mentioned means comprise means for controlling a cooling medium adapted to withdraw heat from the cooler.

17. A recooling device for the cooling fluid of an internal combustion engine, comprising a cooler, a conduit from the engine to the cooler, a conduit from the cooler to the engine, first thermostatic control means responsive to the temperature of the cooling fluid for controlling the circulation of cooling fluid, means for delivering a further cooling medium adapted to abstract heat in the cooler, second thermostatic control means responsive to the temperature of the cooling fluid in said conduit for controlling the supply of said cooling medium, both said control means being so calibrated relatively to each other that upon an increase of temperature of 1 the cooling fluid the second said control means are rendered operative at a higher temperature of the cooling fluid than the first said control means thereby to exert an increased cooling action.

18. A device according to claim 17 wherein air is used as the further cooling medium and the means for supplying the air comprise an adjustable fan.

FRIEDRICH K. H. NALLINGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,558,009 Giesler h Oct. 20, 1925 1,820,035 Stokes Aug. 25, 1931 1,837,564 McCaleb Dec. 22, 1931 1,921,042 Roos Aug. 8, 1938 2,341,789 Justus Feb. 15, 1944 

